Paramendozavilite is a rare secondary molybdenum mineral that typically forms as soft, yellow earthy coatings in oxidized ore deposits. It is structurally related to mendozavilite and is primarily identified via chemical analysis due to its inconspicuous appearance.

Hardness

Mohs

Luster

Vitreous

Streak

Very pale yellow

Transparency

Semitransparent

mineralrareMendozavilite Group family

Paramendozavilite

Hardness: 1
Luster: Vitreous
Streak: Very pale yellow
Transparency: Semitransparent

Is this paramendozavilite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch paramendozavilite with a known reference. Paramendozavilite sits at Mohs 1, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: very pale yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: yellow, light yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: powdery aggregates, crusts.

Often confused with

Paramendozavilite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Ferrimolybdite

Mohs 1-2

How to tell apart: Streak differs, so Paramendozavilite leaves very pale yellow, Ferrimolybdite leaves pale yellow; luster reads vitreous on Paramendozavilite and adamantine to silky, earthy on Ferrimolybdite.

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Often found alongside paramendozavilite

Minerals reported to co-occur with paramendozavilite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: NaAl₄Fe₇(PO₄)₅(PMo₁₂O₄₀)(OH)₁₆·56H₂O
Mohs hardness: 1
Density: 3.35 g/cm³
Colors: Yellow Light yellow
Streak: Very pale yellow
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Powdery aggregates, crusts
Cleavage: One, perfect
Rarity: Rare
Uses: Collector
Host rock: In the oxidized zone of a molybdenum-bearing pegmatitic breccia in granodiorite

Where rockhounds find paramendozavilite

Classic worldwide localities

San Judas mine, Cumobabi molybdenum deposit, southwest of Cumpas, Sonora, Mexico (type locality)

Field-hunting tip

Where it forms: In the oxidized zone of a molybdenum-bearing pegmatitic breccia in granodiorite. If you start seeing mendozavilite, biotite, kaolinite in float, you are in the right ground. Typical habit: powdery aggregates, crusts. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify paramendozavilite?+

Mohs hardness is 1. Luster: vitreous. The streak is very pale yellow. Common colors include yellow, light yellow.

Where is paramendozavilite found?+

Notable localities include San Judas mine, Cumobabi molybdenum deposit, southwest of Cumpas, Sonora, Mexico (type locality).

What rocks look like paramendozavilite?+

Paramendozavilite is most often confused with Ferrimolybdite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with paramendozavilite?+

Paramendozavilite commonly co-occurs with Mendozavilite, Biotite, Kaolinite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does paramendozavilite form in?+

Where it forms: In the oxidized zone of a molybdenum-bearing pegmatitic breccia in granodiorite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is paramendozavilite used for?+

Paramendozavilite is used in collector.

Find paramendozavilite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.